Rubber gloves have been extensively used in household applications, various industrial applications such as food industries and electronic parts production industries, and medical applications. It has been conventionally required that these rubber gloves have a good stretchability even upon application of a smaller force thereto and a good followability to finger motion so as to prevent users' hands from being tired even when wearing for a long period of time (a good touch and feel), are free from breaking during wearing (sufficiently high tensile strength and elongation at break), and exhibit a capability of retaining a tight-fitting condition (a good persistence of close fitting).
Hitherto, there have been frequently used rubber gloves obtained by dip-forming natural rubber latexes. However, the rubber gloves made of natural rubber latexes have such a fear that some users tend to undergo allergy to proteins contained in a rubber component thereof even in a trace amount. Therefore, there have been conventionally proposed gloves made of synthetic rubber latexes which are free from the above drawback.
For example, in U.S. Pat. No. 5,910,533, there have been proposed gloves obtained by dip-forming a dip-forming composition containing a carboxyl-modified conjugated diene-based rubber latex which is produced by subjecting a monomer mixture containing a conjugated diene monomer in an amount of 80 to 99% by weight to emulsion copolymerization and has a glass transition temperature of −50° C. or lower. However, the gloves proposed in U.S. Pat. No. 5,910,533 tend to be insufficient in tensile strength notwithstanding an excellent touch and feel and a sufficient elongation at break thereof.
In U.S. Pat. No. 6,627,325, there have been proposed gloves obtained by dip-forming a dip-forming composition containing a copolymer latex which is produced by subjecting a monomer mixture containing 5 to 65% by weight of an aromatic vinyl monomer, 35 to 90% by weight of a conjugated diene monomer and 0.5 to 10% by weight of an unsaturated acid monomer to emulsion copolymerization and has a toluene insoluble content of 85% by weight or less. More specifically, U.S. Pat. No. 6,627,325 discloses gloves formed from the copolymer latex obtained by emulsion-copolymerizing the monomer mixture containing 34% by weight of styrene. However, the gloves proposed in U.S. Pat. No. 6,627,325 tend to be ill-balanced between touch and feel and tensile strength and insufficient in persistence of close fitting notwithstanding a sufficient elongation at break thereof.
Further, Japanese Patent Application Laid-open No. 131812/2001 discloses gloves obtained by dip-forming a styrene-butadiene rubber latex having a glass transition temperature of 20° C. or lower which satisfy such a condition that a ratio of a tensile stress thereof as measured after 6 min from 100% elongation thereof, to an initial tensile stress thereof as measured immediately after reaching the 100% elongation (stress retention rate) is in the range of 30 to 50%. More specifically, in Japanese Patent Application Laid-open No. 131812/2001, there are disclosed gloves produced from the styrene-butadiene rubber latex having a relatively high styrene content. However, the gloves disclosed in Japanese Patent Application Laid-open No. 131812/2001 tend to be insufficient in touch and feel and persistence of close fitting.